Spraying head

ABSTRACT

A spraying head for the humidification of the intake air of a piston engine, said spraying head comprising at least one nozzle ( 3 ) for supplying a liquid humidifying the intake air into the air intake duct or into a space leading to the air intake duct of the engine. The spraying head ( 1 ) is movable between at least two positions, a first position (FIG.  2   a ), in which first position the spraying head is retracted, and a second position (FIG.  2   b ), in which second position the spraying head is protruding.

BACKGROUND OF THE INVENTION

The present invention relates to a spraying head as defined in thepreamble of claim 1 for humidifying intake air with an aqueous mist.

The exhaust gases of piston engines, in particular diesel engines,contain many kinds of noxious combustion products. At the highcombustion temperatures, the combustion process in the cylinder of apiston engine produces nitrogen oxides (NOx), which are emitted togetherwith the exhaust gases into the atmosphere. Because of the negativeenvironmental effects of nitrogen oxide emissions, efforts areundertaken to minimize their production.

As is known, adding water to the combustion process reduces thegeneration of nitrogen oxides. This phenomenon is based on the coolingeffect of water. In practice, the introduction of water into thecombustion process in a piston engine is often implemented by injectingwater into the intake air. These arrangements are advantageous inrespect of the shaft efficiency of the engine. The maximum amount ofwater introduced into the combustion space of the engine may be thatamount which will remain in gaseous form in the intake air pressure andtemperature conditions.

It has been established that introducing water mist into the intake airis a very advantageous and effective method of reducing noxiousemissions. The spraying heads disclosed by the invention are usedespecially in connection with the humidification of the intake air ofengines. When the spraying head is mounted in its position ofapplication in the air intake duct of the engine, e.g. in connectionwith a turbocharged diesel engine before and/or after the compressor ofthe turbocharger, before and/or after a possible intercooler, it issubjected to very demanding conditions. The intake air flow rate in theair intake duct is e.g. of the order of 80 m/s. The temperature may alsobe fairly high, e.g. above 100 degrees C. In addition, the nozzles usedmust not be an obstruction to the intake air flow when they are not inuse. An additional impediment may be the clogging of the nozzlesespecially when the nozzle head is not in use.

The object of the invention is to achieve a completely new type ofspraying head that allows the intake air to be humidified when necessaryand that forms no impediment to the intake air flow when not in use.

The spraying head of the invention is characterized in that the sprayinghead 1 is movable between at least two positions, a first position, inwhich first position the spraying head is retracted, and a secondposition, in which second position the spraying head is protruding.

The spraying head of the invention is additionally characterized by whatis stated in claims 2-11.

The solution of the invention has numerous significant advantages. Byimplementing the spraying head so that it pops up when activated and isretracted when in non-active state, a spraying head solution is achievedthat forms no obstruction to intake air flow when not in use. Inaddition, the solution disclosed allows the nozzles to remain clean.Providing the spraying head holder with a guide element and the sprayinghead, preferably its shank, with a mating element for the guide surfacemakes it possible to maintain a desired directional orientation of thenozzles. By providing the nozzle head with several nozzles, veryeffective humidification of intake air is achieved. By using the liquidto be sprayed as a pressure medium, a very advantageous and efficientsolution is achieved. By providing a spring element for returning thespraying head into the retracted position, a faster and more effectivetransition to the retracted position is achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be described in detail by the aidof an example with reference to the attached drawing, wherein

FIG. 1 presents a spraying head according to the invention,

FIG. 2 a presents a sectional view of a spraying head according to theinvention in a non-active position and mounted on an air intake duct,

FIG. 2 b presents a sectional view of a spraying head according to theinvention in an active position and mounted on an air intake duct,

FIG. 3 a presents a sectional view of a second spraying head accordingto the invention in a non-active position,

FIG. 3 b presents a sectional view of a second spraying head accordingto the invention in an active position,

FIG. 4 presents a sectional view of a spraying head according to theinvention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1, 2 a and 2 b present an embodiment of the spraying head of theinvention. A spraying head for humidifying the intake air of a pistonengine, said spraying head 1 comprising at least one nozzle 3 forsupplying a liquid humidifying the intake air into the air intake duct 5or into a space leading to the air intake duct of the engine. Thespraying head is movable between at least two positions, a firstposition, in which first position the spraying head is retracted, and asecond position, in which second position the spraying head 1 isprotruding. In the non-active state, in the first position (FIG. 2 a, 3a), the spraying head is in a retracted position, whereas in the activestate, in the second position (FIG. 2 b, 3 b), at least one nozzle 3 ofthe spraying head extends to a position inside the air intake ductrelative to the level of the edges of the spraying head holder 2 orand/or the interior surface of the air intake duct 5.

The holder 2 is provided with at least one guide element 13, and thespraying head, preferably its shank part 7, with at least one matingsurface 14 matching the guide element for keeping the spraying head inthe desired orientation. The guide element 13 is e.g. a groove to whicha ridge in the shank element, aligned in the direction of motion, isfitted. The guide element may also consist of e.g. rolling elements,such as balls or rollers, with a counter element 14 movably fittedbetween these.

The spraying head 1, preferably its shank part 7, and the holder 2 arearranged to function as a cylinder-piston combination in which thespraying head, preferably its shank part 7, is provided with a pistonpart 6 and the holder 2 comprises a cylinder chamber 8, the piston partbeing movably fitted in it. In the embodiment in FIG. 2 a, pressuremedium is supplied from the inlet 9 through a pipe element (not shown)into the cylinder chamber space below the piston 6 from the distant end16 of the holder 2 relative to the air intake duct 5. By the action ofthe pressure medium, the piston moves upwards in the figure, therebycausing the spraying head 1 mounted on the shank part 7 to move to thesecond position shown in FIG. 2 b. The pressure medium is therebyadmitted from the chamber 8 via the channel 11 provided in the shankpart 7 to the nozzle 3, from where it Is injected into the air intakeduct. The channel 11 is typically provided with a throttle element 17.The piston part 6 is provided with a sealing element 12 or equivalent toprovide a sliding fit between it and the interior surface of thecylinder chamber 8.

Arranged in connection with the spraying head are means for moving thespraying head 1 from the protruding position into the retractedposition. Typically, the system comprises a spring element 10 arrangedbetween the spraying head 1 and the holder 2 to move the spraying headfrom the protruding position to the retracted position. The springelement is preferably placed between the piston element 6 and the endpiece of the holder part 2 adjoining the air intake duct 5. The springis a helical spring, which is compressed when the spraying head movesinto the protruding position. When the pressure of the pressure mediumacting on the piston falls below the desired value, the spraying head ismoved to the retracted position by the action of the spring force and/ora possible pressure acting in the air intake duct.

The spraying head is secured to the wall 5 of the air intake ducttypically by a rigid joint, using e.g. fastening means 4, such as screwsor bolts, at its flange 15. The wall 5 of the air intake duct isprovided with an opening for the spraying head. In the embodiment inFIG. 2 a, the spraying head, at least its nozzles 3, as seen in thedirection of motion of the spraying head, remain outside the imaginarysurface formed by the inner edges of the opening in the wall of the airintake duct, i.e. the edges on the interior side of the air intake duct.If the spraying head is of a substantially cylindrical form, then thenozzles typically open to the cylindrical surface. Similarly, if thespraying head has a conical form, then the nozzles open to the conicalsurface. Typically, the nozzles open to the lateral surface of thespraying head.

The spraying head comprises at least one first channel 11 for conveyinga medium to at least one nozzle 3. The spraying head comprises at leastone second channel 21 for conveying a second medium to at least onenozzle 3. The spraying head 1 comprises at least two nozzles 3. Thespraying head 1 is used for spraying a liquid mist, especially watermist. The spraying head 1 is moved from the first position to the secondposition by the action of a pressure medium.

FIGS. 3 a and 3 b present another embodiment of the spraying head of theinvention, wherein two mediums can be fed into the nozzle 3. A liquid,typically water, is supplied through the inlet aperture 9 into thechamber 8, from where it can flow through the first channel 11 to thenozzle 3. The pressure of the first pressure medium forces the sprayinghead 1 from the first position (FIG. 3 a) to the second position (FIG. 3b). Provided in the shank 7 of the spraying head is a second channel 21,into which a second pressure medium, typically a gas, such as air, issupplied through the second inlet aperture 20. In the embodimentpresented in FIGS. 3 a and 3 b the shank has been made long so that, inthe non-active first position, it extends outwards, in the figuredownwards from the end opposite to the spraying head 1, while in theactive position it extends roughly to the level of the holder end 16. Inthe solution according to this embodiment, the nozzle head is moved fromthe active second position to the first position by the action of thepressure in the air intake duct, said pressure exerting a force on thespraying head 1 end facing towards the air intake duct.

FIG. 4 presents a spraying head 1 according to the invention, sectionedat a plane perpendicular to the longitudinal axis of the spraying head.The spraying head comprises several nozzles 3, to which a pressuremedium is supplied via several channels 11. The spraying head works e.g.as follows. First, the spraying head moves into the active position andspraying is started with one of the first nozzles 3. Next, the sprayingcan be continued by spraying through two nozzles, and finally throughall three nozzles.

The spraying head of the invention is very well applicable for thespraying of a high-pressure medium. The pressure in the piping istypically over 30 bar, preferably over 50 bar, most preferably over 75bar. The nozzles of the spraying head are preferably disposed on alateral surface of the spraying head, being thus protected againstpossible soiling in the non-active state. The pressure of the liquidinjected through the spraying head may be typically between 10-300 bar.The liquid, especially aqueous liquid injected into the air intakeductwork is a fine mist. 50% of the water volume (Dv50) is in the formof droplets typically having a droplet size below 200 micrometers,preferably below 100 micrometers and more preferably below 50micrometers. The form of the spraying head, the number of nozzles andtheir orientation may vary depending on the application. It is alsopossible to supply different mediums to the nozzle, such as water andgas. The figure does not show the nozzles in detail, but they may bereplaceable depending on the application. The nozzles are therefore of atype such that they produce a spray of fine mist when supplied withliquid under a high pressure. Many kinds of nozzles of this category areknown, e.g. from fire extinguishing technology employing water mist. Forexample, specifications WO 92/20454 and WO 94/06567 disclose nozzlesthat produce a water mist at a high pressure. Naturally, other types ofnozzles may also be used, e.g. specification WO 01/45799 discloses yetanother nozzle.

It is obvious to the person skilled in the art that the invention is notlimited to the embodiments described above, but that it may be variedwithin the scope of the claims presented below.

1. Spraying head for the humidification of the intake air of a pistonengine, said spraying head comprising at least one nozzle (3) forsupplying a liquid humidifying the intake air into the air intake ductor into a space leading to the air intake duct of the engine,characterized in that the spraying head (1) is movable between at leasttwo positions, a first position, in which first position the sprayinghead is retracted, and a second position, in which second position thespraying head is protruding.
 2. Spraying head according to claim 1,characterized in that, in a non-active state, the spraying head is inthe retracted first position, while in an active state, in the secondposition, at least one of the nozzles (3) of the spraying head extendsto a position inside the air intake duct relative to the level of theedges of the spraying head holder (2) or and/or the interior surface ofthe air intake duct (5).
 3. Spraying head according to claim 1,characterized in that the holder (2) is provided with at least one guideelement (13) and the spraying head with at least one guide elementmating surface (14) for keeping the spraying head in a desiredorientation.
 4. Spraying head according to claim 1, characterized inthat the spraying head (1), preferably its shank part (7), and theholder (2) are arranged to function as a cylinder-piston combination inwhich the spraying head, preferably its shank part (7), is provided witha piston part (7) and the holder (2) comprises a cylinder chamber (8),the piston part being movably fitted in it.
 5. Spraying head accordingto claim 1 characterized in that the spraying head arrangement comprisesmeans for moving the spraying head (1) from the protruding position intothe retracted position.
 6. Spraying head according to claim 1,characterized in that a spring element (10) is arranged between thespraying head (1) and the holder (2) for 8 moving the spraying head fromthe protruding position to the retracted position.
 7. Spraying headaccording to claim 1, characterized in that the spraying head comprisesat least one first channel (11) for conveying a pressure medium to atleast one nozzle (3).
 8. Spraying head according to claim 1,characterized in that the spraying head comprises at least one secondchannel (21) for conveying a second pressure medium to at least onenozzle.
 9. Spraying head according to claim 1, characterized in that thespraying head (1) comprises at least two nozzles (3).
 10. Spraying headaccording to claim 1, characterized in that the spraying head (1)comprises at least one second channel for conveying a medium to anothernozzle.
 11. Spraying head according to claim 1, characterized in thatthe spraying head sprays a liquid mist, especially water mist. 12.Spraying head according to claim 1, characterized in that the sprayinghead (1) is moved from the first position to the second position by theaction of a pressure medium.